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J Chem Theory Comput. 2017 Apr 11;13(4):1509-1517. doi: 10.1021/acs.jctc.6b01181. Epub 2017 Mar 22.

Quantifying Allosteric Communication via Both Concerted Structural Changes and Conformational Disorder with CARDS.

Author information

1
Department of Biochemistry and Molecular Biophysics, and ‡Center for Biological Systems Engineering, Washington University in St. Louis , St. Louis, Missouri 63110, United States.

Abstract

Allosteric (i.e., long-range) communication within proteins is crucial for many biological processes, such as the activation of signaling cascades in response to specific stimuli. However, the physical basis for this communication remains unclear. Existing computational methods for identifying allostery focus on the role of concerted structural changes, but recent experimental work demonstrates that disorder is also an important factor. Here, we introduce the Correlation of All Rotameric and Dynamical States (CARDS) framework for quantifying correlations between both the structure and disorder of different regions of a protein. To quantify disorder, we draw inspiration from methods for quantifying "dynamic heterogeneity" from chemical physics to classify segments of a dihedral's time evolution as being in either ordered or disordered regimes. To demonstrate the utility of this approach, we apply CARDS to the Catabolite Activator Protein (CAP), a transcriptional activator that is regulated by Cyclic Adenosine MonoPhosphate (cAMP) binding. We find that CARDS captures allosteric communication between the two cAMP-Binding Domains (CBDs). Importantly, CARDS reveals that this coupling is dominated by disorder-mediated correlations, consistent with NMR experiments that establish allosteric coupling between the CBDs occurs without a concerted structural change. CARDS also recapitulates an enhanced role for disorder in the communication between the DNA-Binding Domains (DBDs) and CBDs in the S62F variant of CAP. Finally, we demonstrate that using CARDS to find communication hotspots identifies regions of CAP that are in allosteric communication without foreknowledge of their identities. Therefore, we expect CARDS to be of great utility for both understanding and predicting allostery.

PMID:
28282132
PMCID:
PMC5934993
DOI:
10.1021/acs.jctc.6b01181
[Indexed for MEDLINE]
Free PMC Article

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